Load-dependent brake pressure proportioning valve

Claim 2

A brake pressure proportioning valve comprising: a stepped cylinder having a pressure medium inlet and a pressure medium outlet to brakes to be controlled; a stepped piston disposed axially movable in said cylinder relative to said inlet and said outlet to proportion the pressure medium coupled to said outlet dependent upon the load of the axle having said brakes to be controlled; a control tappet disposed coaxially within said cylinder to control the axial movement of said piston dependent upon a force applied to said control tappet proportional to said axle load, said control tappet having a smaller diameter than the adjacent end of said piston; a lever mechanism connected to said control tappet to apply said force thereto; and a first pressure medium connection disposed internally of said piston to interconnect said control tappet and said inlet and to apply pressure medium to the end of said control tappet adjacent said piston to improve the control action of said control tappet.

Claim 3

A valve according to claim 1, wherein Said stepped cylinder includes a first cylindrical chamber having a first given diameter, a second cylindrical chamber having a second given diameter greater than said first given diameter, and a first transverse wall interconnecting said first and second chambers; said stepped piston includes a first portion slidably sealed to the inner surface of said second chamber, a second portion slidably sealed to the inner surface of said first chamber, and a second transverse wall interconnecting said first and second portions; said inlet is connected to a third chamber disposed between said first portion and said first chamber; said outlet is connected to a fourth chamber disposed between said first portion and an end wall of said second chamber; said inlet and said outlet are interconnected by a second pressure medium connection disposed within said stepped piston; said second connection has disposed therein a first closing element having a first valve tappet in contact with said end wall; a fifth chamber is disposed within said second chamber adjacent one end of said second portion spaced from said first portion; said control tappet extends axially through said cylinder in a slidably sealed relation into said fifth chamber, said control tappet having a smaller cross-section than the cross-section of said one end of said second portion; and said first pressure medium connection has a second closing element having a second valve tappet in contact with said control tappet in said fifth chamber, said first pressure medium connection being opened when said control tappet shifts said second closing element to an open position.